Make fire

Use a rock to harvest a clear piece of ice—lake ice at least a few feet from the shore is a good bet. Use the heat from your bare hands to shape it into an inch-thick lens that’s convex (bulging out) on both sides. Then, holding your ice lens with gloved hands, concentrate the sun like a magnifying glass. (Note: If you think you may someday use this–or just want to impress your friends–practice like crazy. Everything about this technique is hard.)

Signal for help

Ice can make a decent reflector if properly shaped into a convex geometry that concentrates light. Shape clear ice (as above) and practice shining your lens on a nearby surface to get a sense for how it works. Use this to signal aircraft. Need dispersed light instead? Put your headlamp against a chunk of cloudy ice.

Fix broken gear

In subzero conditions, Canadian survival instructors have long used ice as a makeshift glue by wetting moss, lichens, or cloth, wrapping the patch of vegetation or cloth around objects such as broken tent poles, and waiting for the bandage to freeze into place.

Add sticking power

Make your tent stakes or deadman anchors stronger in snow by dumping a cup or two of water (sourced from a creek or bottle) on them and letting it freeze.

Treat injuries

Ice reduces swelling and pain and can even help slow blood flow from an injury. Apply ice in 20-minute increments and check the wound to ensure it’s not getting waxy or white with cold. Keep pressure on bleeders until the flow stops.

Bonus: Stay Awake

If there’s a situation where you must stay awake, such as after suffering a concussion, tie a piece of ice to the top of your tent so it drips on your forehead. They don’t call it water torture for nothing.